1. Field of the Invention
The present invention relates to an electric hydraulic control device for a construction vehicle having work tools
2. Description of the Prior Art
In prior art, the work tools of a construction vehicle has been controlled in such a way that an operator manipulates operation levers. The movement of the operation lever is directly applied to the spool of a control valve via a link, rod, or the like so as to change the direction of hydraulic fluid of a hydraulic cylinder for operating the work tool. However, in the case of a large construction vehicle, it is difficult for the operator to operate the spool of the control valve directly by his own operating force.
Besides, since a link and rod are employed, much time has been required for the installation or removal of the control system at the time of power line change, with the resultant shortening of operation time. Moreover, automatic controlling of construction vehicles without the operator's operation has been impossible.
In addition, in the case of a bulldozer having work tools such as a blade 1 and a ripper 2, locking levers such as a pin-puller lever to be used for the insertion and removal of a pin 3, which is for installing the transmission lever for vehicle travel, the blade lever, the ripper lever and the ripper 2 on the vehicle body, has been effected by operating rock levers provided together with each of the operation levers. However, lever operation at the time of start and stop of work has been complicated due to multiplicity of lock lever operations.